1. Field of the Invention
The present invention relates to a setting tool for anchoring a spreading anchor having an anchor rod and an expansion sleeve, with the setting tool including a sleeve-shaped body having an end surface, an axial blind bore opening at the end surface, and a lead-in surface for receiving axial impacts and provided at a rear end of the sleeve-shaped body remote from the end surface at which the blind bore opens.
2. Description of the Prior Art
For anchoring of a number of conventional attachment elements in a constructional component, specially formed setting apparatuses became necessary. E.g., mandrel-like setting tools are used for anchoring spreading anchors having a sleeve provided with an expansion region and an inner thread, and an axially displaceable expanding member. This setting tool has several sections, which have different diameters, and an annular stop shoulder. The setting tool is inserted through a rear opening of the sleeve until the front end of the setting tool abuts the expanding member. The mostly cone-shaped expanding member is driven into the through-bore of the expansion sleeve by axial impacts applied to the rear end of the setting tool until the stop shoulder of the setting tool abuts the rear edge of the expansion sleeve. The expanding member, upon being driven in, expands radially the expansion region of the sleeve, with the spreading anchor being forcelockingly anchored in a preliminary formed receiving bore.
The known setting tool has a wedge-shaped projection formed on the annular stop shoulder and which form, upon the tool being impacted, an indentation in the rear edge of the expansion sleeve. This indentation shows that the expanding member has been adequately driven in the through-bore of the expansion sleeve, and that the expansion region of the expansion sleeve has been completely expanded. This setting tool can be used only for anchoring spreading anchors which have an expansion sleeve provided with an inner thread. However, the indentation, which is formed in the rear edge of the expansion sleeve, is often barely visible, e.g., when the spreading anchors seats relatively deeply in the receiving bore. With a constructional element being attached, the edge of the expansion sleeve is mostly not visible any more. In this case, it is not any more possible to establish, without dismounting the attached constructional element, whether the spreading anchor has been properly anchored.
Another category of attachment elements is represented by spreading anchors including an anchor rod and an expansion sleeve with a radially expanding expansion region. In most cases, the anchor rod has an outer thread, which serves as load application means, and a head provided at a front end of the anchor rod and having an ever increasing diameter. For anchoring the spreading anchor in a preliminary formed bore, the expansion sleeve is driven over the anchor rod head whereby the expansion region of the sleeve is expanded radially. In most cases, the expansion sleeve is driven by axial impacts onto the head portion of the anchor rod which is supported on the bore bottom. When the spreading anchor is formed as an undercut self-cutting anchor with the expansion tabs formlockingly engaging in a formed undercut, the expansion sleeve, in addition to being driven in axially, is also rotated. As a result of the rotation, the radially expanding expansion tabs form an undercut in the vicinity of the bore bottom. The anchoring of the spreading anchor is insured by a formlocking connection of the expansion tabs with the undercut formed in the receiving bore during the setting process.
For setting spreading anchors of this category, primarily, sleeve-shaped setting tools are used. These setting tools have an axial bore in which the anchor rod is received during a setting process. The end surface associated with the bore opening contacts the rear edge of the expansion sleeve. The sleeve is driven over the anchor rod head portion with axial impacts applied to the rear end of the setting tool. For transmission of a rotational torque to the expansion sleeve, in case of anchoring of an undercut self-forming spreading anchor, the front end surface of the sleeve-shaped setting tool is provided with projections engageable in corresponding recesses formed in the rear edge of the expansion sleeve. The opposite end of the setting tool is provided with a shank to be received in a chuck of an electrical hand-held drill, e.g., a percussion drill. Upon actuation of the percussion drill, the setting tool rotates and percussion drives the expansion tool onto the head portion. The radially expanding expansion tabs of the rotatable sleeve form an undercut in the bore wall upon the sleeve being displaced over the head portion of the anchor rod.
For controlling the setting process of a spreading anchor, there are provided setting marks. The setting marks can, e.g., be formed as flutes provided on the outer surface of the setting tool. The alignment of the flutes with the bore edge shows that a setting process has ended, and the expansion sleeve has been driven sufficiently deep. In order for these flutes to provide an adequate information of a reliable anchoring of the spreading anchor in a bore, the bore should be formed with an exactly predetermined depth, with a too deep formed bore, the marks on the setting tool may not provide a reliable information of whether the expansion sleeve has been expanded sufficiently wide, which can negatively affect the resulting holding values. The setting marks can also be provided on the anchor rod, e.g., by providing color marks on the anchor rod circumference. The arrangement of the color marks is so selected that they become visible only when the sleeve has already been driven along the head portion of the anchor rod a sufficient amount. However it may happen, with a relatively deep bore, that the color marks would disappear into the bore and would be barely visible. After an attachment of a constructional component, the marks on the anchor rod are mostly not visible as they are usually covered by the constructional element. Therefore, a correct setting of this spreading anchor, in particular, when it is formed as an undercut self-cutting spreading anchor, cannot be determined visually after the end of the setting process and mounting of the constructional component.
Accordingly, an object of the present invention is to eliminate the drawback of the prior art setting tools. Another object of the present invention is to provide a setting tool for a spreading anchor having an anchor rod and an expansion sleeve, in particular for an undercut self-cutting spreading anchor, which would enable to conduct a visual control of the setting in a simple way after the end of the setting process. The visual control of the setting should show whether the spreading anchor has adequately been anchored in the constructional component. Further, an easy inspection of the attachment points after the attachment of the constructional element should be insured.